Biology 203 Exam 1

Front 1

Cancer

Back 1

the loss of cell cycle control

Front 2

Prophase 1 of Meiosis

Back 2

unique process occurs called synapsis

Front 3

Synapsis

Back 3

involves physical pairing of homologous chromosomes

Front 4

Tetrad

Back 4

arrangement of two homologous chromosomes

Front 5

Chiasmata

Back 5

at this stage sometimes chromatids break and connect with other chromatids, this is know as crossing over and occurs on chiasmata

Front 6

Source of Variation

Back 6

1. Independent Assortment
2. Crossing Over
3. Random Fertilization
4. Mutation

Front 7

Amniocentesis

Back 7

amniotic fluid bathing the fetus contains sloughed off cells and can be used to check karyotype
14-16 weeks
Used to look for Trisomy 21

Front 8

Choronic Villi Sampling (CVS)

Back 8

suction extraction of tiny samples of fetal tissue from the placenta
8-10 weeks

Front 9

Allele

Back 9

alternative forms of the same gene relating to a characteristic
(trait = characteristic)

Front 10

Phenotype

Back 10

observabel effect of the presence of a gene or combination of genes

Front 11

Genotype

Back 11

description of an organisms genetic makeup, regardless of whether it is expressed or not

Front 12

Dominant Trait

Back 12

characteristic expressed whether heterozygous or homozygous

Front 13

Recessive Trait

Back 13

masked by the presence of a dominant allele in heterozygous form, expressed only in homozygotes

Front 14

Law of Segregation of Alleles

Back 14

*for a specific trait controlling genes occur in pairs in somatic cells of the adult
*during sex cell formation, the two alleles separate
*fertilization=segragated alleles from two parents, combined randomly to form new 2n individual

Front 15

Mendels Second Law
(Principle of Independent Assortment)

Back 15

unlinked genes on separate chromosomes

Front 16

Incomplete Dominance

Back 16

one allele not completely dominant over the other so heterozygote has phenotype intermediate between phenotypes of the two homozygotes

Front 17

Codominance

Back 17

both alleles separately manifest in the phenotype

A,B,O Blood Group

Front 18

Pleiotropy

Back 18

ability of a single gene to have multiple phenotypic effects

ex. sickle cell anemia

Front 19

Epistasis

Back 19

interaction between two non-allegic genes in which one modifies the phenotypic expression of the other

Front 20

Polygenetic Inheritance

Back 20

many genes contributing to phenotype, most human genes are polygenetic

Front 21

Nature vs. Nurture

Back 21

phenotype depends on environmental as well as genes

Front 22

Rule of Multiplication

Back 22

the probability of two independent events occuring simultaneously is the product of their individual probabilities

Front 23

Rule of Addition

Back 23

if there are multiple ways to achieve a certain outcome you must add the probabilities of each independent way to get the overall probability for that event

Front 24

Pedigree Analysis

Back 24

square = male
circle = female

Front 25

Huntingtons Disease

Back 25

degenerative disease of nervous system develops at 35-45 years of age, irreversible and fatal

Front 26

Marfan Syndrom

Back 26

disorder of connective tissue (Abraham Lincoln)

Front 27

Morgan's genetic Symbols

Back 27

w+ = wildtype

Front 28

Linked Genes

Back 28

genes on the same chromosome tend to be inherited together

Front 29

Genetic Recombination

Back 29

production of offspring with new combinations of traits different from those of their parents

Front 30

Recombinatino Frequency Equation

Back 30

number of recombinants/ total number of offspring

Front 31

Nature vs. Nurture

Back 31

phenotype depends on environmental as well as genes

Front 32

Rule of Multiplication

Back 32

the probability of two independent events occuring simultaneously is the product of their individual probabilities

Front 33

Rule of Addition

Back 33

if there are multiple ways to achieve a certain outcome you must add the probabilities of each independent way to get the overall probability for that event

Front 34

Pedigree Analysis

Back 34

square = male
circle = female

Front 35

Huntingtons Disease

Back 35

degenerative disease of nervous system develops at 35-45 years of age, irreversible and fatal

Front 36

Marfan Syndrom

Back 36

disorder of connective tissue (Abraham Lincoln)

Front 37

Morgan's genetic Symbols

Back 37

w+ = wildtype

Front 38

Linked Genes

Back 38

genes on the same chromosome tend to be inherited together

Front 39

Genetic Recombination

Back 39

production of offspring with new combinations of traits different from those of their parents

Front 40

Recombination Frequency Equation

Back 40

number of recombinants/ total number of offspring*100

Front 41

Linkage Map

Back 41

use recombination frequency between genes to map the sequence of linked genes on a particular chromosome

Front 42

Cytological Map

Back 42

pinpoints actual location of genes and real distance between them

Front 43

Physical Map

Back 43

based on nucleotide positions from genome sequencing and gene isolation

Front 44

Lyon Hypothesis

Back 44

one of the two x chromosomes contracts into dense barr bodies

Front 45

Inactivation of X chromosomes

Back 45

methyl groups are attached to cytosine, barr bodies are highly methylated

Front 46

XIST Gene

Back 46

"X inactive specific transcript"
RNA that interacts with X chromosome and maintains inactivation

Front 47

Aneuploidy

Back 47

zygote has abnormal chromosome number

Front 48

Trisomy

Back 48

2n+1

Front 49

Monosomy

Back 49

2n-1

Front 50

Polyploidy

Back 50

more than two complete chromosome sets

Front 51

Down Syndrome

Back 51

trisomy of the 21 chromosome
1 in every 700 births
individuals have 47 chromosomes mostly from non-disjunction during gamete formation in 1 of the parents
correlates with the age of the mother

Front 52

Turners Syndrome

Back 52

X0
1 in 5000
only know human monosomy
short stature, no secondary sex characteristic develop, phenotypically female, internal sex organs don't mature
translocation of the 21 chromosome to the 15 chromosome